Rotary sleeve-valved two-cycle engine



Jan. 2, 1923,

ROTARY SLEEVE VALVED Two CYCLE Emma.

FILED MAR. 25, 1920 2 SHEETSSHEET I TWP , 1 1,441,111 T. W. PATERSON. H

Jan. 2, 1923.

. T. W. PATERSON. ROTARY Suzev 1,441,! 11 a VALVED Two CYCLE ENGINE FlLED MAR. 25 l 920.

2 sussrs-snsu 2 ma ls/v70? 997 596 o/v portion of the incoming theexhaust, and to.

Patented .Tan. 2, 1923.

e stares recites wn'rsoi'v Parmesan, or mvnnroon, ENGLAND.

no'renr srinnvn-vnrvnn 'rwooronn .ENGIKE.

Application filed March 25, 1920. v seria1ivu. 'aes, 7'6e.

5 call whom iii nay concern; I

Be it known that I, THOMAS Wirrson lhrrnnsoiv, a subject of the KingofGreat Britain, and a resident of Liverpool, England, have inventedcertain new and useful Improvements in Rotary Sleeve-valved Two-CycleEngines, ofwhich the following is a specification. I I

This invention relates to a two-stroke cycle internal combustionenginehaving a rotary sleeve valve. In two-stroke cycle engin'es inorder to enable the exhaust gases to be eiiectively swept from thecylinder, the inlet should be disposed at one end exhaust at the other.As such an arrangement, however, would in the usual typeof engine valvenecessitate one of the valves being continually open the inlet andexhaust ports have been disposed .in the further part of the cylinderuncovered by the piston on its outward stroke. Such an arrangement,however, is inefiective inasmuch as the spent gases are not swept outand a great combustible mixture passes out with avoid this means havebeen provided such as an upstanding web or rib on the piston which actedto deflect the I incoming combustible mixture well into the head of thecylinder, the spent gases being thus swept out therefrom. Such anarrangement, is,

. however, very disadvantageous. Also, where.

compression of the combustible mixture is eitected in the crank case theinlet port for the combustible mixture to the crank case is disposed ashigh as possible in the'cylinder wall and in consequence such port isonly uncovered momentarily by the piston. The object of the presentovercome these difiiculties, in a two-stroke cycle engine by positivelycontrolling, otherwise than solely by the piston, the inlet of thecombustible mixture to the crank case and into and from the firing spaceof the cylinder by means of a rotary sleeve valve. The invention may beadapted for a twin opposed cylinder unit engine.

According to this invention, therefore, the cylinder of the engine isprovided with a rotary sleeve valve having three ports cooperatingrespectively with three other ports in the cylinder wall. The pistonworks within the sleeve valve and fits gastightly therein. The inletport from' the carburetter to the crank case is disposed compara- 'tageof.

and the f in which the piston operates. as a shaft,

invention is to tively low down in the cylinder and sleeve valve, sothat this port may be uncovered immediately the piston begins to rise onits inward ticks and thus the maximum suction effect of the piston indrawing in a cl'iarge from the carburetter is: taken advan- The inletport't'o the lirin space from the bre k case, is disposed at t is lowset point of the cylinder uncovered by the top ofthe piston onitsoutward stroke, and the eiihaiist ports are disposed near the top ofthe sleevevalveiana cylinder. 1

I The invention isillustrated in the accomoanying drawings in whichFig. 1. is a longitudinal section showing the invention aplied to anengine, comprisingtwo opposed cylinders on opposite sides of the crankthe sleeve valves. being driven by mechanism enclosed in the crank case.Fig. 2. is a "rragmnt rysection showing a modiing gea being exterior tothe crank case and cylinders, Fig. 3. is a diagrammatic tied drive forthe sleeve valvesythe 'driv-' the carburetter ports when; the piston ison the bottom dead centre, while Fig. 4. is an analogous section showingthe position of the inlet ports to the cylinder from the crank case whenthe piston is in the same position. Fig.6. shows the position of theexhaust ports and carburetter ports when the piston is on the top deadcentre, and Fig. 6. shows the position of the inlet ports .fromthe crankcase when the piston is in thesameZpos-ition. v I I i In carrying outthe invention, the cylinders 1 or theengi'ne, which may be water-.jacketed at 2 in any usual, manner, are provided with rotary sleevevalves I 3, each hav- Ytlir'ee ports co-operating with three other portsinth'e "cylinder wall. The pistons 4; work gastightly in the sleevevalves. The cylinder inlet port 5 from the carburetter to the crank caseis disposed low down in the cylinder as is the corresponding port 5 inthe sleeve valve, so that this carburettor port may be uncoveredimmediately the piston begins to rise on the suc tion stroke and thusthe maximum suction efl'ect ofthe piston to draw ina charge from thecarburettor is taken advantage of. The cylinder inlet port 6 to thefiring space of the cylinder communicates by way of suitable ducts '7with corresponding ports 8 in the crank case and such inlet ports 6 andthe corresponding sleeve ports 6 are disposed at the lowest partuncovered by the piston. 4- on its outward stroke, as shown in the topcylinder of Fig. 1. the exhaust ports 9 in the cylinder andQ in thesleeve valve being disposed near the top".

In operation, therefore, supposing the piston to be retreating into thecylinder head the rotation of the sleeve valve is about. to uncover thecarburetter port 5 to the crank case as the piston begins to uncover thecorresponding port 5 in the sleeve, and in this way full advantage maybe taken of the entire suction stroke of the piston. I On the return oroutward stroke of the piston the combustible mixture is compressed andpassed from the crank case through the inlet ports 6, G, in the cylinderand sleeve valve to the firing space of the cylinder, assistinginsweeping out the exhaust gases through the upper open exhaust ports 9,9', in the cylinder and sleeve valve. Owing to the combined openingmovement of the ports with such an arrangement, due to the rotationalmovementof the sleeve valve and the longitudinal covering and uncoveringmovement of the piston, the inlet port from the crank case 6 to thecylinder may be opened and closed very quickly, a full charge of thecombustible mixture being permitted to enter the firing cylinder whenthe piston is on the outer part of its stroke, and for the same reasonthe exhaust port may be made to close quickly as the piston commencesits inward compression stroke and thus prevent any great portion of thefresh charge a being entrained with the spent gases out through theexhaust.

Such an arrangement of two-stroke cycle engine may beadapted for useWhere two cylinders are arranged on opposite sides of the crank shaft asin the form illustrated, the cylinders being thus in twin opposedformation. In this construction, each sleeve valve may be rotated froma'helical or other gear wheel 10 on the crank shaft ll engag ing ahelical or other gear 12 on the lower edge of the'sleeve valve, thevalve operating gear being thus entirely enclosed in the crank case 13,or f desired, the sleeve valve may be driven from an exterlor mechanismsuch as from helical or other gear 14 on the crank shaft engaginghelical or other gear 15 on a. side shaft- 16, Fig. 2, the ends of theside shaft being coupled by chain and sprocket gear 17 to a stub spindle18 on the sleeve valve passing through the cylinder heads, or thesleevesmay be driven otherwise. The sleeve valves at their lower endsand also in the region of the stub driving spindles are fitted with ballraces 19, 20, which take the longitudinal thrust due to the drag of thepiston.

In such an arrangement the sleeve valve and the cylinder being eachprovided with three ports, the co-operation of these ports to effect theentrance of the combustible mixture to the crank casefor compression,from the crank case to the firing cylinder, and from the cylinder to theexhaust may be very effectively attained, and inasmuch as I the openingand closing of these ports is not merely dependent upon the longitudinalmovement of the piston but is controlled by the combined longitudinalmovement of the piston and the rotary movement of the sleeve valve, bymakingthe size of the ports as re quired any desired period of openingof these valves maybe secured, and a much more effective type of engineobtained than is possible with other 'ar 'angements where rotary sleevevalves are not fitted.

I claim:

An internal combustion engine including a base, a cylinder, a sleevevalve rotatable within said cylinder, a piston slidable Within saidsleeve valve, a by-pass communicating between the base and the interiorof the sleeve valve, a fuel inlet port in said cylinder and a similarport in the sleeve valve, said ports when alined providing communicationindependent of said by-pass and directly between a source of fuel supplyand said base, means for exhausting products of combustion from saidsleeve valve, and means for rotating said valve.

In testimony whereof I affix my signature in presence of two witnesses.

' THOMAS WATSON PATERSON. VVitnessesr A. J.'DAVIES, E. HEGINBOTHAM.

